Activity of Santiaguito, Turrialba, Sabancaya and Ruapehu.

The Santiaguito Volcano Observatory reports abundant and sustained degassing of a white color from a height of 800 meters above the crater which extends in a southwest and south direction.

At night, incandescence was observed in the crater of the Caliente dome and in the lava flow in a west-southwest direction. Weak, moderate and strong avalanches continue to be recorded at the front and in the middle of the lava flow in a west and southwest direction as well as on the southern flank.

The volcano maintains high activity. Due to blocky lava extrusion within the Caliente Dome in a west-southwest direction and unstable material within the crater there is a likelihood of moderate to strong pyroclastic flows, staying near or in the riverbeds near the slopes of the volcano.

Source: Insivumeh

Santiaguito - Conred photo archives / 03.02.2022 - one click to enlarge

At 06:18:00 local time on April 25, 2022, an eruptive episode was recorded at the Rincon de la Vieja volcano, the height reached by the column is unknown due to the visibility conditions of the site.
Duration of the activity: 1 minute.
The seismic activity is higher, compared to yesterday.
An increase in the intensity of the low frequency tremor is observed.

Recently, the gas plumes from the Poas and Turrialba volcanoes have become more visible and condensed due to climatic conditions (increase in relative humidity linked to the start of the rainy season). No significant changes in activity.

Source: Ovsicori

Turrialba - degassing on 04.25.2022 / 5:00 p.m. - Ovsicori webcam - one click to enlarge

Poas - thermal convection in the lake and fumarolic degassing on 04.25.2022 / 07:50 - Ovsicori webcam - one click to enlarge

Between April 18 and 24, 2022, the eruptive activity of Sabancaya remained at moderate levels, with an average of 37 explosions per day, accompanied by plumes of gas and ash reaching 2,300 meters above the summit.

The I.G.P. detected 140 earthquakes associated with the circulation of internal magmatic fluids during this week, and VT earthquakes related to rock fracturing.

The deformation monitoring by GNSS technique does not show any significant anomalies.

Ten thermal anomalies, from max. 34 MW, associated with the presence of a lava body on the surface of the crater are revealed by satellite monitoring.

The volcanic alert remains at naranja, with a non-accessible zone of 12 km radius around the crater.

Sources: I.G.Peru (uploaded 25.04.2022), Mirova and Mounts Project

Sabancaya - activity from 18 to 24.04.2022 - Doc. I.G.Peru

Sabancaya - image Sentinel-2 bands 12,11, 8A from 04.24.2022 / 2:57 p.m. - via Mounts project - one click to enlarge

High volcanic unrest continued at Mount Ruapehu for five weeks. This increased volcanic unrest is primarily manifested by volcanic tremors, gas production, and heat flux into the summit crater lake. The level of volcanic tremor has varied over the past week but remains high overall. This tremor episode now represents the longest and strongest combined tremor period recorded in the past 20 years.

Crater Lake (Te Wai ā-moe) temperature has remained around 37°C (range 36-38°C) for the past three weeks. Although the temperature has not increased, our modeling predicts that a significant amount of heat (about 200-300 MW) is still needed to maintain this high lake temperature. Laboratory analyzes of a lake sample taken on April 15 show no change in Crater Lake's water chemistry since March 31.

The lake's static temperature and lack of chemical response indicate that shallow processes below the crater lake are not reflected in lake conditions. We did not observe an increase in magnesium concentration that would have indicated a potential subsurface magma-water interaction. We will continue to regularly sample the crater lake to monitor any changes in water chemistry.

The sustained nature of the volcanic unrest, coupled with the strong volcanic tremor signals, high gas production and hot lake, remains indicative of processes driven by molten rock (magma) interacting with the geothermal system within the volcano. at shallow depth (0.5-2 km).

The most likely outcome of this episode of unrest over the next four weeks is still that no eruptive activity occurs, as no eruption has followed unrest for the past 15 years. If eruptive activity follows these unrest, it is expected to be small scale initially. Such an eruption would primarily affect the summit area, with lahars further downstream as well - such as the September 2007 eruption or the slightly larger events of April 1975 or June 1969. Only if eruptions continued would we would expect to see larger ash eruptions developing with substantial impact further outside Tongariro National Park.

The chances of a prolonged eruptive episode or a larger eruption, such as the one that occurred in 1995-96 with wider ashfall impacts, are higher than two months ago, but remain very unlikely. Such an eruption would most likely only follow a sequence of smaller eruptions.

The interpretation of this activity is consistent with elevated volcanic unrest at the Elevated Level and therefore the Volcanic Alert Level remains at Level 2. The Aviation Color Code remains at Yellow.

Source: GeoNet 26.04.2022

Ruapehu - the summit with traces of ash and lahars from the eruption of the day before - photo 26.09.2007 GeoNet in GVP